Allmaa-markšeiderivõrkude orienteerimine vertikaalse kaeveõõne kaudu Estonia kaevanduse näitel [Magistritöö. Juhendaja: E. Väli]

Almost fifty years has passed since the opening of the Estonia oil shale mine. During this period several changes have occurred in the geodetic system of the country Estonia, which have not been adopted into the survey networks of the mine. Similarly, no inspection of the direction angle of the mine survey networks has been carried out for almost thirty years.

The aim of the current thesis is to conduct an orientation survey of the underground survey networks of the Estonia mine. This is done by using a vertical shaft for checking the accuracy of the underground survey networks and creating a basis for transferring the planar coordinate system of the mine from the existing local system to L-EST97, which is used elsewhere in Estonia, and for transferring the Balti 1977 height system (BK77) to European height system EH2000. Unification of the geodetic systems of the mine and the country will significantly reduce the operations a surveyor has to perform daily and will increase the accuracy of coherence between the underground shafts and the surface. A ventilation shaft of the Estonia mine not yet in operation was used for the orientation surveys performed in this study. Two plumblines were lowered into the mine through the new ventilation shaft and their positions were measured on the surface using the L-EST97 coordinate system, and
underground using the local coordinate system. As a result of the orientation surveys, two underground points with known coordinates were created, as well as a line with a known azimuth. This
data was then used for performing an inspection of the direction angle of underground survey networks and for determining the error arising from the conversion of coordinates from L-EST97
system to the local system.

The inspection of the direction angle of the underground survey networks performed in the framework of this thesis did not identify a significant deviation from the expected, or the direction angle
determined by previous underground surveys. The error arising from the conversion of coordinates did not exceed the previously assumed limits, either. Thus, connecting the underground shafts with
the surface can be performed with sufficient accuracy for the purposes of the mine, even with the existence of this error.

This thesis launched the process of modernisation of the geodetic system of the Estonia mine. However, unfortunately one orientation survey cannot provide enough data for transferring the planar
coordinate and height systems of the entire mine. It is necessary to continue this work and repeat the orientation surveys at least two more times, so that the transition to the national geodetic system
would give accurate and trustworthy results.